Heaney will get an MRI on Monday, Angels manager Mike Scioscia said Sunday, to determine if there has been any progress made in the six weeks since he received the shot. Richards will have his MRI done on June 27.
Both are dealing with tears to the ulnar collateral ligament on their pitching elbow, and looked to be out for the rest of this season and probably most, if not all, of the 2017 season. If all goes well for Heaney and Richards, however, each could possibly pitch again in the Majors this season.
Heaney has not pitched since April 5, and Richards since May 1.
The stem-cell therapy took stem cells from Heaney and Richards' bone marrow and injected them into the UCL to see if that would allow it to heal instead of opting for surgery. Richards said all he can do now is wait to see if his patience pays off.
"I've been told that the longer you wait with this, it's even better with this stem-cell stuff," Richards said. "We'll re-evaluate it. It's supposed to be an 8-12-week process anyway, but if I get some good news on week six, hopefully it'll be better."
Richards said he still maintains his "robot-like" workout regimen, replacing his normal pitching days with days that have heavier weightlifting and cardio workouts. The waiting has still been hard, however, as Richards compared the time on the sidelines to when a ruptured left patella tendon in his knee ended his 2014 season.
"It's not fun," he said. "I wake up every day and anything that I pick up, my first instinct is to throw it. It's hard to shut down what you do."
• Angels left fielder Daniel Nava is expected to begin a Minor League rehab assignment with Class A Advanced Inland Empire within the next couple of days, Scioscia said. Nava has not played since sustaining a left groin strain on May 16 against the Dodgers.
• Angels bullpen coach Scott Radinsky made his way back to Angel Stadium this weekend for the first time since undergoing triple bypass heart surgery while the team was in Oakland in April. Scioscia said he was encouraged by Radinsky's progress, though he may not be ready to return to coaching yet.
"It's good to see Scott," Scioscia said. "He's feeling much better. He has a little more time before he's going to be cleared to come out here and work our bullpen, but feeling much better. Hopefully in the next couple weeks, we can get him back."
Fabian Ardaya is a reporter for MLB.com based in Anaheim. This story was not subject to the approval of Major League Baseball or its clubs.